Pretty sure some of you have seen some variation of this but for those who were thinking about starting up a planted tank and didn't want to spend hundreds of dollars on co2 generators for the plants inside the tank.
He says it's cheap but you are going to need some way to get holes (probably a drill) into the water bottles
No need get a piece of metal that is a bit smaller than the airline tubing and just heat it up with a lighter. It will slide cleaning through and make a nice hole.
Make sure that you have an air pump running at night when you are still running CO2 or you will gas your fish. Also make sure your lighting will actually be bright enough to actually use CO2 or else there is just no reason to. It depends on how much light you're using.
I was thinking, if I just took a betta cup of water out of the tank at night and put the diffuser/airline in it for the CO2 while the plants don't need it, would that work instead of buying an airpump and air stone?
Also, could I theoretically use an airline T to split the CO2 between two smaller tanks? ((Ten gallon and 2.5))
Running an airstone at night, while helpful, is by no means necessary. DIY CO2 produces nowhere near enough CO2 to gas your fish. It's not that big of a deal leaving the system running throughout the night. I've even heard of some people who run pressurized or paintball systems throughout the night (low bps though).
It's an NPT, but I've seen a lot of NPTs benefit from added CO2, so I was considering it. ((Especially since my 2.5 is failing rather spectacularly after doing really well.)) Just average potting soil under a cap of sand for my 10 and gravel for my 2.5. A compact fluorescent for the 2.5, I forget exactly which kelvins but in the recommended range for plants. Straight fluorescent for the 10, but it needs a new bulb, the old was too much and was growing algae, now it has the one that was in it, which is only 5000 kelvins, which I'm hoping to rectify as soon as my foot gets better(sprain). I dose a few drops of flourish every couple of days in the ten gallon for my stem feeders and my floaters, since it's not fully established yet and I'm still doing water changes. I put maybe two or three drops of the in the 2.5 a week for the same reason, plus it's fairly lightly stocked, so not much natural ferts.
First off, plants also release CO2 at night and taking in oxygen, that means that running it, will run the risk of gassing your fish. People that don't really understand how plants use CO2 and everything shouldn't start using CO2 as it can heavily impact your tank. Too much CO2 you get pH drops and that can seriously stress your fish. Please don't say I know people that do this...
Your system sounds like it could benefit from CO2. How are you going to diffuse it though? There are many different ways you can, I am just curious.
Actually, my filter has an aeration valve on top, I figured I'd hook it to that. ((Or if I'm concerned about suction, just stick it in this piece it has for taking in air and tape it up, so there's not a vaccum on the mixture. Sounds confusing but it makes sense if you could see the pieces. The 2.5 I'd either use a ladder or a glass diffuser.
Yes, running CO2 definitely does carry risks. However, DIY CO2 doesn't create enough CO2 for it to actually gas the fish at night. With pressurized systems, it becomes risky, and an airstone or shutting the system down at night is more of a necessity, however.
Feel free to take a look at these - offers opinions from hobbyists much more experienced than I am:
I've had good diffusing experiences hooking DIY CO2 systems to filters, but it gets a little loud for me sometimes when the impeller shreds the bubbles - maybe it's just my filter though. If you want to go for a cheap alternative to a glass diffuser or a ladder, just stick a piece of wooden chopstick (you can use the ones you get from restaurants), and it diffuses pretty nicely.